Artists have traditionally used supports or substrates such as canvas, wood panels, and paper for paintings and drawings. These materials are fragile, flexible and susceptible to atmospheric changes which can cause expansion of the support material. Over time, these inherent properties can cause cracking, warping, and loss of integrity of the substrate and/or the artist's materials applied to the substrate.
Artists have long sought other materials for use as a substrate or support for the application of traditional media that would avoid these problems and provide a permanent and rigid substrate to which various artists' materials can be applied.
To be suitable for use by artists working in such diverse materials as pencil, charcoal, pastels, inks and paints, the substrate must accept and retain the medium in a manner similar to canvas or paper, must permit the artist to modify and/or remove the medium from the surface of the substrate during development of the-work, and most importantly, the final work must adhere permanently to the substrate.
Prefinished exterior architectural panels have been developed that possess several characteristics that would make them desirable for use as a substrate or support for the application of artists' materials. Having been developed for use in exterior building construction, architectural panels are rigid and dimensionally stable; their polymeric finishes have the advantage of sunlight and weather resistance and can be considered permanent as compared to the traditional artists' substrates. However, such prefinished architectural panels suffer the drawback of having shiny, slick finishes that are impervious to essentially all artists' materials. It has also been found that for those few classes of artists' materials that can be applied to the prefinished panels, almost all can be readily removed by wiping or light scraping, as with the fingernail.
Another important consideration is the ability to cut the architectural panels to the size desired. Panels having factory applied finishes must be able to be cut and shaped with conventional hand tools or small power tools that are available to the artist. The finish should not crack or separate along cutting lines. Also, of importance is the weight or gage of the metal to which the finish is applied. Since the architectural panels may only be available from the manufacturer in certain specified large sizes, the materials of fabrication should be relatively light in weight so that the panels can be moved and worked by the artist without special equipment. Especially hardened metal panels that require specialized tools and/or equipment for cutting and shaping would not be useful.
A class of prefinished architectural panels that has been found to have many desirable characteristics are composites comprising two or more metal sheets with a thermoplastic core between the sheets. Of particular utility are prefinished architectural panels comprising two sheets or webs of aluminum having between them, and bonded together by, a thermoplastic core. This aluminum composite has the advantages of being relatively light in weight, and adapted for cutting and shaping with conventional hand tools, such as saws and files, and with small power tools. Such aluminum composite panels can also be bent and rolled to assume curvilinear shapes using conventional methods and tools.
The finishes applied to exterior architectural panels must be suitable for the practice of the invention. The finishes must be hard, but be susceptible to being dulled or roughened in preparation of the surface for application of the artists' materials. Suitable finishes are found among polymeric materials. It has been found that finishes of particular utility are selected from the group consisting of polyester and fluorocarbon coatings.
Both the polyester and fluorocarbon finishes are manufactured with smooth monolithic surfaces and are available in colors and a variety of gloss levels. This slick non-porous surface is not at all receptive to the direct application of artists' grade materials by hand. The impervious surface coating is resistant to bonding with artists materials such as paints and pastels which, in practice, also prove difficult to manipulate. Wet paint materials tend to "bead up" and fail to adhere properly, while most drawing mediums glide over the surface without marking. Some paints, such as artists' oils and enamels, can be made to bond to the factory finished coating surface by heating the panel to which the paint has been applied.